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71.
72.
In this paper we describe the structure of surjective isometries of the space of all generalized probability distribution functions on ? with respect to the Kolmogorov-Smirnov metric. 相似文献
73.
74.
Tertuliano Franco Patrícia Gonçalves Adriana Neumann 《Journal of statistical physics》2014,156(5):975-997
We obtain the fluctuations for the occupation time of one-dimensional symmetric exclusion processes with speed change, where the transition rates (conductances) are driven by a general function \(W\) . The approach does not require sharp bounds on the spectral gap of the system nor the jump rates to be bounded from above or below. We present some examples and for one of them, we observe that the fluctuations of the current are trivial, but the fluctuations of the occupation time are given by a fractional Brownian Motion. This shows that, in general, the fluctuations of the current and of the occupation time are not of same order. 相似文献
75.
M. Patrício J. L. Santos F. Patrício A. J. C. Varandas 《Journal of mathematical chemistry》2013,51(7):1729-1746
The use of the theory of splines to approximate the potential energy surface in molecular dynamics is examined. It is envisaged that such an approximation should be able to accurately capture the potentials’ behavior and be computationally cost effective, both for one-dimensional and $n$ -dimensional problems with $n$ arbitrary. In this regard, the problem of dimensionality is pinpointed, with shape-preserving splines emerging as a viable alternative for fitting surfaces in multidimensional spaces. An algorithm is also presented to allow the use of non-uniform meshes with high accuracy fitting and less interpolation points. 相似文献
76.
Patrício S. Letelier 《General Relativity and Gravitation》1979,10(7):631-632
The J. Scherk and J. H. Schwarz generalization of a Peres solution is shown to be the Peres solution in a different system of coordinates. 相似文献
77.
Patrícia Matias José Manuel Lopes Sébastien Laforge Patrick Magnoux Michel Guisnet Fernando Ram?a Ribeiro 《Reaction Kinetics and Catalysis Letters》2008,95(1):193-201
The main features of methylcyclohexane (mch) and n-heptane (n-C7) transformation at 350°C were compared for fresh samples of HMWW, HMFI and HFAU zeolites. With both reactions, the behavior
of HMWW was between those of the medium HMFI and large pore HFAU zeolites. Thus, the values of turnover frequency (TOF) and
of the TOFmch/n-C7 ratio were similar with HMWW and HMFI and much higher with HFAU. In contrast, small differences were found between product
distributions over HMWW and HFAU but large differences between HMWW and HMFI. These observations can be explained by alkane
transformation in the large supercages with 10-MR apertures of HMWW: the narrow apertures limit diffusion of the mch within
the supercages, but not the diffusion of the products which are therefore typical of the transformation within large cages
hence without any steric limitation. 相似文献
78.
Tedim J Bessada R Patrício S Magalhães AL Freire C Gurman SJ Hillman AR 《Langmuir : the ACS journal of surfaces and colloids》2008,24(16):8998-9005
[Ni( salen)] complexes bearing different crown ether receptors were electropolymerized to give films whose voltammetric signatures responded to Ba2+. In line with DFT calculations, X-ray absorption spectroscopy (XAS) near the Ni K-edge showed the nickel local environment in the monomers and their corresponding polymers (in the presence or absence of barium) to be identical. However, the expectation of crown size-dependent barium local environment (based on geometry and donor atom availability) was not found. XAS near the Ba K-edge showed that Ba2+ in the films coordinated to only two oxygen donors, irrespective of crown size. This surprisingly low coordination number (compared to solution species) is accompanied by a higher barium/crown ratio than the anticipated 1:1 stoichiometry. The implications of these effects for design and performance of sensors based on metal ion recognition chemistry are discussed. 相似文献
79.
Santiago PS Neto Dde S Gandini SC Tabak M 《Colloids and surfaces. B, Biointerfaces》2008,65(2):247-256
Fluorescence quenching of meso-tetrakis-4-sulfonatophenyl (TPPS(4)) and meso-tetrakis-4-N-methylpyridil (TMPyP) porphyrins is studied in aqueous solution and upon addition of micelles of sodium dodecylsulfate (SDS), cetyltrimethylammonium chloride (CTAC), N-hexadecyl-N,N-dimethyl-3-ammonio-1-propanesulfonate (HPS) and t-octylphenoxypolyethoxyethanol (Triton X-100). Potassium iodide (KI) was used as quencher. Steady-state Stern-Volmer plots were best fitted by a quadratic equation, including dynamic (K(D)) and static (K(S)) quenching. K(S) was significantly smaller than K(D). Frequency-domain fluorescence lifetimes allowed estimating bimolecular quenching constants, k(q). At 25 degrees C, in aqueous solution, TMPyP shows k(q) values a factor of 2-3 higher than the diffusional limit. TPPS(4) shows collisional quenching with pH dependent k(q) values. For TMPyP quenching results are consistent with reported binding constants: a significant reduction of quenching takes place for SDS, a moderate reduction is observed for HPS and almost no change is seen for Triton X-100. Similar data were obtained at 50 degrees C. For CTAC-TPPS(4) system an enhancement of quenching was observed as compared to pure buffer. This is probably associated to accumulation of iodide at the cationic micellar interface. The attraction between CTAC headgroups and I(-), and repulsion between SDS and I(-), enhances and reduces the fluorescence quenching, respectively, of porphyrins located at the micellar interface. The small quenching of TPPS(4) in Triton X-100 is consistent with strong binding as reported in the literature. 相似文献
80.
Patrícia A. Russo M. Manuela L. Ribeiro Carrott Peter J. M. Carrott 《Adsorption》2008,14(2-3):367-375
Adsorption-desorption isotherms of toluene, methylcyclohexane and neopentane were determined on a silica MCM-41 material of
pore diameter ∼3.4 nm over the temperature range 258 K to 308 K (278 K for neopentane). The isosteric enthalpies of adsorption
were determined from the isotherms at the various temperatures. It was found that the isotherms of toluene and methylcyclohexane
have a similar variation with the temperature, exhibiting hysteresis at 268 K and at lower temperature, while the adsorption
of neopentane is reversible at all temperatures. The three organic adsorptives interact differently with the silica surface
and the isosteric enthalpies of adsorption indicated that methylcyclohexane has the weakest interaction and toluene the strongest.
A slight increase in the adsorption enthalpy at the beginning of the capillary condensation step is observed with methylcyclohexane
and neopentane but not with toluene. 相似文献